1. Field of the Invention
The present invention relates to self-playing pianos and control apparatuses for pianos that automatically play music on demand by manipulating piano keyboards and pedals in consonance with received play data. More particularly, the present invention relates to a technique for using the soft pedals of pianos to produce soft sounds.
Self-playing acoustic pianos, and apparatuses for automatically playing acoustic pianos, are in current, practical use. To play music, the drive mechanisms of these devices manipulate piano keyboards and pedals in consonance with prerecorded play data.
Automatic playing mechanisms are used with both upright pianos and grand pianos, but there is a big gap in the quality of the music obtained from these two instruments. The quality of the music produced by an upright piano is relatively poor, whether an automatic playing mechanism has been built in or has simply been attached. Thus, there is a demand for an upright piano with a built-in automatic playing mechanism, or for an automatic playing apparatus that can be attached to an upright piano, that can produce music comparable in quality to that produced by a grand piano.
2. Description of the Related Art
A conventional self-playing piano, or a conventional apparatus for automatic playing of a piano, incorporates a storage device,. e.g., a floppy disk, that holds play data, including key numbers, key depression force data and time information. When the piano or the apparatus receives a signal to begin playing, via, for example, an operation panel, it reads play data from the storage device and uses this data in its operation of the keyboard and pedals to perform automatic playing.
More specifically, play data constituting event information groups is previously stored in a storage device. As shown by the example in FIG. 4A, one event information group consists of an identification symbol, a key number, key depression force data, and time information.
When playing is initiated, one event information group of the play data is read from the storage device, and the included time information is examined. When the time information corresponds to an execution timing (time) for the read-out event information, procedures for this event information are performed, i.e., keys are depressed or released.
The execution time for an event information group is determined as follows: A time count, which is held by a time counter that counts clock cycles, is compared with the time information in the read-out event information group, and when they correspond it is assumed that the procedures for the event should be performed.
Then, the average electric power is determined, based on information designated in play data, that dictates how strongly, or at What key depression force, selected keys (key numbers) should be depressed, and then solenoids are driven using the determined electric power. Keys coupled to these solenoids are therefore depressed or released at a strength (velocity) relative to the average electric power, and predetermined dynamic music is played.
Unlike for key manipulation, key depression force data is not employed for the depression or release of pedals. Consonant with execution and time data, a constant strength is employed to manipulate pedals.
After the procedures for one event information group have been completed, the next event information group is read from the storage device and the described process is repeated. Music is produced by repeatedly reading and processing event information groups.
In general, acoustic pianos, either uprights or grands, have soft pedals and associated implementing mechanisms. When a soft pedal is depressed, its related mechanism is activated and produces a unique musical effect, hereafter referred to as the "soft sound effect."
The soft pedal mechanisms of current upright pianos and grand pianos differ both in structure and in effect.
More specifically, when the soft pedal of a grand piano is depressed, the keyboard action moves in a predetermined direction to alter the relative positions of the hammers and the strings. As a result, a sound that is produced by a hammer striking three strings while a soft pedal is at rest, for example, is produced by the hammer striking only two strings while the soft pedal is depressed. The soft sound effect obtained by depressing a soft pedal is clearly distinguishable.
On an upright piano, however, when the soft pedal is depressed a hammer rail that holds the hammers in their initial positions is moved in a predetermined direction to position the hammers one third closer to the strings than when the soft pedal is at rest. When, thereafter, hammers strike the strings a soft sound effect is obtained. This effect, however, actually has little aural appeal.
Since an automatic playing apparatus is designed to manipulate pedals and components using solenoids, the soft sound effect obtained is little different from that obtained when a player manually plays a piano.
Because, as described above, grand pianos and upright pianos are structurally different, the soft sound effects provided by them vary greatly. Specifically, the sound quality of grand pianos is far superior to that of upright pianos. When the same playing software is used to automatically play a grand piano and an upright piano, there is a distinct difference in the quality of the sounds that are produced.
On an upright piano, when the hammer rail that determines the positions of the hammers has greater momentum, and moves closer to the strings to enhance the soft sound effect provided by a soft pedal, the speed of its movement may cause the hammers to strike strings by accident and produce unwanted tones.
Because the soft sound effect of a self-playing upright piano has very little aural appeal, there are some self-playing pianos that do not have a soft pedal mechanism.